asn.dev

Observed topology

AS237 MERIT-AS-14

Upstreams 10 carry this network
Downstreams 31 this network carries
Adjacent (IPv4) 40
Adjacent (IPv6) 15

Transit

Upstream networks

inferred

Networks observed carrying traffic for AS237: the AS immediately before it in a routing path. Ranked by how many paths showed the relationship, which reflects how widely it is used, not how much traffic crosses it.

ASNetworkTypeFamiliesPaths seen
AS1299Arelion Sweden ABTransitIPv4 IPv61,991
AS174Cogent Communications, LLCTransitIPv4 IPv6956
AS6939Hurricane Electric LLCTransitIPv4 IPv6777
AS2914NTT America, Inc.TransitIPv4 IPv6689
AS11537Internet2UnclassifiedIPv4 IPv6417
AS7018AT&T Enterprises, LLCResidentialIPv4 IPv6222
AS11164Internet2EducationIPv4 IPv694
AS14907Wikimedia Foundation Inc.HostingIPv4 IPv690
AS293ESnetUnclassifiedIPv483
AS3303Swisscom (Schweiz) AGResidentialIPv482

Inferred from path position, not from any declaration by either party. A network appearing here is carrying these routes; whether that is a paid transit arrangement, a backup, or something else is not something routing data can tell you.

Transit

Downstream networks

inferred

Networks for which AS237 was observed as the last hop before the origin, meaning it appears to provide them transit.

ASNetworkTypeFamiliesPaths seen
AS11206Ferris State UniversityEducationIPv41,983
AS25609Detroit Medical CenterUnclassifiedIPv41,080
AS36375University of MichiganUnclassifiedIPv4 IPv6966
AS231Michigan State UniversityUnclassifiedIPv4 IPv6407
AS400238PIE&GUnclassifiedIPv4225
AS27274Central Michigan UniversityUnclassifiedIPv4 IPv6220
AS62618Michigan Technological UniversityEducationIPv4185
AS394769University of Michigan - FlintUnclassifiedIPv4126
AS22251Regional Educational Media Center 1 (REMC1)UnclassifiedIPv4125
AS62676University of Michigan - DearbornUnclassifiedIPv4124
AS1638Mott Community CollegeEducationIPv4123
AS1432Albion CollegeUnclassifiedIPv4117
AS396470Lansing Community CollegeUnclassifiedIPv4104
AS46825Coldwater Board of Public UtilitiesUnclassifiedIPv4 IPv697
AS229Merit Network Inc.UnclassifiedIPv4 IPv695
AS22217Calvin CollegeUnclassifiedIPv475
AS177University of MichiganUnclassifiedIPv666
AS402639WashtenawUnclassifiedIPv463
AS393817Lake Michigan CollegeUnclassifiedIPv462
AS46241Washtenaw ISDUnclassifiedIPv462
AS400927Barger Creek WirelessUnclassifiedIPv461
AS19106Andrews UniversityUnclassifiedIPv4 IPv661
AS15099County of MonroeUnclassifiedIPv457
AS11494Kellogg Community CollegeEducationIPv443
AS393665Baker CollegeUnclassifiedIPv438
AS32285Henry Ford CollegeUnclassifiedIPv423
AS395945Holland Board of Public WorksUnclassifiedIPv416
AS3730Aquinas CollegeEducationIPv414
AS30154Davenport UniversityUnclassifiedIPv414
AS53263Grand Rapids Community CollegeUnclassifiedIPv410
AS40044Bronson Healthcare Group, Inc.UnclassifiedIPv46

Adjacency

Adjacent networks

55 shown

Every AS seen directly next to AS237 in a routing path, in either direction.

ASNetworkTypeFamiliesPaths seen
AS1299Arelion Sweden ABTransitIPv4 IPv64,454
AS174Cogent Communications, LLCTransitIPv4 IPv62,294
AS11206Ferris State UniversityEducationIPv41,983
AS6939Hurricane Electric LLCTransitIPv4 IPv61,610
AS2914NTT America, Inc.TransitIPv4 IPv61,266
AS11537Internet2UnclassifiedIPv4 IPv61,129
AS25609Detroit Medical CenterUnclassifiedIPv41,080
AS36375University of MichiganUnclassifiedIPv4 IPv6966
AS7018AT&T Enterprises, LLCResidentialIPv4 IPv6487
AS231Michigan State UniversityUnclassifiedIPv4 IPv6468
AS11164Internet2EducationIPv4 IPv6346
AS293ESnetUnclassifiedIPv4232
AS400238PIE&GUnclassifiedIPv4225
AS27274Central Michigan UniversityUnclassifiedIPv4 IPv6220
AS3303Swisscom (Schweiz) AGResidentialIPv4202
AS62618Michigan Technological UniversityEducationIPv4185
AS394769University of Michigan - FlintUnclassifiedIPv4126
AS22251Regional Educational Media Center 1 (REMC1)UnclassifiedIPv4125
AS62676University of Michigan - DearbornUnclassifiedIPv4124
AS1638Mott Community CollegeEducationIPv4123
AS1432Albion CollegeUnclassifiedIPv4117
AS396470Lansing Community CollegeUnclassifiedIPv4104
AS46825Coldwater Board of Public UtilitiesUnclassifiedIPv4 IPv697
AS229Merit Network Inc.UnclassifiedIPv4 IPv695
AS14907Wikimedia Foundation Inc.HostingIPv4 IPv690
AS22217Calvin CollegeUnclassifiedIPv475
AS177University of MichiganUnclassifiedIPv666
AS402639WashtenawUnclassifiedIPv463
AS393817Lake Michigan CollegeUnclassifiedIPv462
AS46241Washtenaw ISDUnclassifiedIPv462
AS400927Barger Creek WirelessUnclassifiedIPv461
AS19106Andrews UniversityUnclassifiedIPv4 IPv661
AS15099County of MonroeUnclassifiedIPv457
AS11494Kellogg Community CollegeEducationIPv443
AS393665Baker CollegeUnclassifiedIPv438
AS32285Henry Ford CollegeUnclassifiedIPv423
AS395945Holland Board of Public WorksUnclassifiedIPv416
AS30154Davenport UniversityUnclassifiedIPv414
AS3730Aquinas CollegeEducationIPv414
AS53263Grand Rapids Community CollegeUnclassifiedIPv410
AS40044Bronson Healthcare Group, Inc.UnclassifiedIPv46

Adjacency is not the same as peering. Being next to each other in a path covers paid transit, settlement-free peering and customer connections alike, and routing data cannot distinguish them. Treat this as "these networks exchange routes", nothing more specific.

Interconnection

Exchange presence

recorded

Internet exchanges where Packet Clearing House has a port recorded for AS237, largest fabric first. An exchange is shared switching where networks interconnect directly rather than paying a transit provider to carry traffic between them, so turning up at one is a deliberate choice about how this network wants to be reached. Each name opens that exchange's own page, with its peering LANs and every other network recorded on it. Recorded at 2 exchanges across 1 country and 1 region.

ExchangeLocationTheir addressMember ports
Equinix Internet Exchange ChicagoChicago, United States208.115.136.39280
Detroit Internet ExchangeDetroit, United States209.124.52.12102

Unlike the tables above, this is recorded rather than inferred. An address on a peering LAN is at that exchange by definition. Two carve-outs all the same. Member ports counts every participant at the exchange, not this network's ports, so read it as a size proxy. And an absent exchange means PCH has no record of it, not that the network is not there.

Provenance

Where this comes from

Derived from routing tables collected at 2026-08-08 10:00 UTC by route-views2,rrc00, as seen from 75 BGP vantage points across 74.02M route entries. These are observations from those vantage points, not a complete or authoritative view of the internet.

Cross-check against RIPEstat or BGP.tools, which observe from a different and larger set of vantage points.

Exchange presence comes from a separate dataset: the directory collected 2026-08-09 by Packet Clearing House (https://www.pch.net/ixp/data), covering 1,327 exchanges and 93,164 recorded member ports, licensed CC BY-NC-SA 3.0.

PeeringDB is the better-known directory and is deliberately not the source here: its acceptable-use policy forbids the bulk storage this needs. The two answer different questions anyway. PeeringDB reports what an operator declares about itself; this reports what PCH has recorded.